crsf.h File Reference

RC protocol definition for CSRF (TBS Crossfire). More...

#include <stdint.h>
#include <px4_platform_common/defines.h>

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Classes
struct	crsf_frame_header_t
struct	crsf_frame_t

Macros
#define	CRSF_FRAME_SIZE_MAX   30
#define	CRSF_PAYLOAD_SIZE_MAX   (CRSF_FRAME_SIZE_MAX-4)

Functions
__EXPORT int	crsf_config (int uart_fd)
	Configure an UART port to be used for CRSF. More...
__EXPORT bool	crsf_parse (const uint64_t now, const uint8_t *frame, unsigned len, uint16_t *values, uint16_t *num_values, uint16_t max_channels)
	Parse the CRSF protocol and extract RC channel data. More...
__EXPORT bool	crsf_send_telemetry_battery (int uart_fd, uint16_t voltage, uint16_t current, int fuel, uint8_t remaining)
	Send telemetry battery information. More...
__EXPORT bool	crsf_send_telemetry_gps (int uart_fd, int32_t latitude, int32_t longitude, uint16_t groundspeed, uint16_t gps_heading, uint16_t altitude, uint8_t num_satellites)
	Send telemetry GPS information. More...
__EXPORT bool	crsf_send_telemetry_attitude (int uart_fd, int16_t pitch, int16_t roll, int16_t yaw)
	Send telemetry Attitude information. More...
__EXPORT bool	crsf_send_telemetry_flight_mode (int uart_fd, const char *flight_mode)
	Send telemetry Flight Mode information. More...

Detailed Description

RC protocol definition for CSRF (TBS Crossfire).

It is an uninverted protocol at 420000 baudrate.

RC channels come in at 150Hz.

Author

Beat Küng beat-.nosp@m.kuen.nosp@m.g@gmx.nosp@m..net

Definition in file crsf.h.

Macro Definition Documentation

CRSF_FRAME_SIZE_MAX

#define CRSF_FRAME_SIZE_MAX   30

Definition at line 52 of file crsf.h.

CRSF_PAYLOAD_SIZE_MAX

#define CRSF_PAYLOAD_SIZE_MAX   (CRSF_FRAME_SIZE_MAX-4)

Definition at line 53 of file crsf.h.

Function Documentation

crsf_config()

__EXPORT int crsf_config

(

int

uart_fd

)

Configure an UART port to be used for CRSF.

Parameters

uart_fd

UART file descriptor

Returns

0 on success, -errno otherwise

Definition at line 147 of file crsf.cpp.

References convert_channel_value(), and CRSF_BAUDRATE.

Referenced by RCInput::cycle().

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crsf_parse()

__EXPORT bool crsf_parse	(	const uint64_t	now,
		const uint8_t *	frame,
		unsigned	len,
		uint16_t *	values,
		uint16_t *	num_values,
		uint16_t	max_channels
	)

Parse the CRSF protocol and extract RC channel data.

Parameters

now	current time
frame	data to parse
len	length of frame
values	output channel values, each in range [1000, 2000]
num_values	set to the number of parsed channels in values
max_channels	maximum length of values

Returns

true if channels successfully decoded

Definition at line 166 of file crsf.cpp.

References CRSF_DEBUG, crsf_parse_buffer(), current_frame_position, MIN, and unsynced.

Referenced by RCTest::crsfTest(), and RCInput::cycle().

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crsf_send_telemetry_attitude()

__EXPORT bool crsf_send_telemetry_attitude	(	int	uart_fd,
		int16_t	pitch,
		int16_t	roll,
		int16_t	yaw
	)

Send telemetry Attitude information.

Parameters

uart_fd	UART file descriptor
pitch	Pitch angle [rad * 1e4]
roll	Roll angle [rad * 1e4]
yaw	Yaw angle [rad * 1e4]

Returns

true on success

Definition at line 478 of file crsf.cpp.

References attitude, write(), write_frame_crc(), write_frame_header(), and write_uint16_t().

Referenced by CRSFTelemetry::send_attitude().

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crsf_send_telemetry_battery()

__EXPORT bool crsf_send_telemetry_battery	(	int	uart_fd,
		uint16_t	voltage,
		uint16_t	current,
		int	fuel,
		uint8_t	remaining
	)

Send telemetry battery information.

Parameters

uart_fd	UART file descriptor
voltage	Voltage [0.1V]
current	Current [0.1A]
fuel	drawn mAh
remaining	battery remaining [%]

Returns

true on success

Definition at line 449 of file crsf.cpp.

References battery_sensor, write(), write_frame_crc(), write_frame_header(), write_uint16_t(), write_uint24_t(), and write_uint8_t().

Referenced by CRSFTelemetry::send_battery().

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crsf_send_telemetry_flight_mode()

__EXPORT bool crsf_send_telemetry_flight_mode	(	int	uart_fd,
		const char *	flight_mode
	)

Send telemetry Flight Mode information.

Parameters

uart_fd	UART file descriptor
flight_mode	Flight Mode string (max length = 15)

Returns

true on success

Definition at line 490 of file crsf.cpp.

References flight_mode, write(), write_frame_crc(), and write_frame_header().

Referenced by CRSFTelemetry::send_flight_mode().

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crsf_send_telemetry_gps()

__EXPORT bool crsf_send_telemetry_gps	(	int	uart_fd,
		int32_t	latitude,
		int32_t	longitude,
		uint16_t	groundspeed,
		uint16_t	gps_heading,
		uint16_t	altitude,
		uint8_t	num_satellites
	)

Send telemetry GPS information.

Parameters

uart_fd	UART file descriptor
latitude	latitude [degree * 1e7]
longitude	longitude [degree * 1e7]
groundspeed	Ground speed [km/h * 10]
gps_heading	GPS heading [degree * 100]
altitude	Altitude [meters + 1000m offset]
num_satellites	number of satellites used

Returns

true on success

Definition at line 462 of file crsf.cpp.

References gps, write(), write_frame_crc(), write_frame_header(), write_int32_t(), write_uint16_t(), and write_uint8_t().

Referenced by CRSFTelemetry::send_gps().

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